Adapting demodulation reference signal configuration in networks using massive mimo

ABSTRACT

Based on the receipt of a demodulation reference signal from a user equipment, a determination can be made by the network node that a demodulation reference signal configuration is not suitable for the condition of a transmission link between the network node and the user equipment. In response to this determination, the demodulation reference signal configuration can be modified.

TECHNICAL FIELD

The present application relates generally to the field of wirelesscommunication, and, more specifically, to adapting demodulationreference signal (DMRS) configuration for networks (including 5G orother next generation networks) employing massive multiple inputmultiple output (MIMO) techniques.

BACKGROUND

Radio technologies in cellular communications have grown rapidly andevolved since the launch of analog cellular systems in the 1980s,starting from the First Generation (1G) in 1980s, Second Generation (2G)in 1990s, Third Generation (3G) in 2000s, and Fourth Generation (4G) in2010s (including Long Term Evolution (LTE) and variants of LTE). Fifthgeneration (5G) access networks, which can also be referred to as NewRadio (NR) access networks, are currently being developed and expectedto fulfill the demand for exponentially increasing data traffic, and tohandle a very wide range of use cases and requirements, including amongothers mobile broadband (MBB) and machine type communications (e.g.,involving Internet of Things (IOT) devices).

The upcoming 5G access network may utilize higher frequencies (e.g., >6GHz) to aid in increasing capacity. Currently, much of the millimeterwave (mmWave) spectrum, the band of spectrum between 30 gigahertz (Ghz)and 300 Ghz is underutilized. The millimeter waves have shorterwavelengths that range from 10 millimeters to 1 millimeter, and thesemmWave signals experience severe path loss, penetration loss, andfading. However, the shorter wavelength at mmWave frequencies alsoallows more antennas to be packed in the same physical dimension, whichallows for large-scale spatial multiplexing and highly directionalbeamforming.

Performance can be improved if both the transmitter and the receiver areequipped with multiple antennas. Multi-antenna techniques cansignificantly increase the data rates and reliability of a wirelesscommunication system. The use of multiple input multiple output (MIMO)techniques, which was introduced in the third-generation partnershipproject (3GPP) and has been in use (including with LTE), is amulti-antenna technique that can improve the spectral efficiency oftransmissions, thereby significantly boosting the overall data carryingcapacity of wireless systems. MIMO techniques can improve mmWavecommunications, and has been widely recognized a potentially importantcomponent for access networks operating in higher frequencies. MIMO canbe used for achieving diversity gain, spatial multiplexing gain andbeamforming gain. For these reasons, MIMO systems, including massiveMIMO systems using a large number of antennas, can be an important partof the 3rd and 4th generation wireless systems, and are planned for usein 5G systems.

The above-described background relating to wireless networks is merelyintended to provide a contextual overview of some current issues, and isnot intended to be exhaustive. Other contextual information may becomefurther apparent upon review of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the subject disclosureare described with reference to the following figures, wherein likereference numerals refer to like parts throughout the various viewsunless otherwise specified.

FIG. 1 illustrates an example wireless communication system which anetwork node device (e.g., network node) communicates with userequipment (UEs), or user devices, in accordance with various aspects andembodiments of the subject disclosure.

FIG. 2 illustrates a diagram showing a UE communicating with a remoteradio unit (RRU) that is coupled to a baseband unit (BBU) device, inaccordance with various aspects and embodiments of the subjectdisclosure.

FIG. 3 illustrates a chart showing the physical uplink control channelformat for long term evolution (LTE) communications.

FIG. 4 illustrates an example of a multi-antenna transmission embodimenthaving multiple antenna ports, in accordance with various aspects andembodiments of the subject disclosure.

FIG. 5 illustrates an example of a schematics of a multi-antennareceiver in the UL (e.g., network node), in accordance with variousaspects and embodiments of the subject disclosure.

FIG. 6 illustrates a graph showing block error rate (BLER) versussignal-to-noise-plus-interference ratio (SINR), with curvesrepresentative of the number of multiple antennas.

FIG. 7 illustrates a block diagram for modifying a demodulationreference signal (DMRS) configuration, in accordance with variousaspects and embodiments of the subject disclosure.

FIG. 8 illustrates a transaction diagram comprising message sequencesfor modifying a DMRS configuration, in accordance with various aspectsand embodiments of the subject disclosure.

FIGS. 9-11 show example flow charts describing operations that can beperformed, in accordance with various aspects and embodiments of thesubject disclosure.

FIG. 12 illustrates an example block diagram of an example mobilehandset, which can be a UE, in accordance with various aspects andembodiments of the subject disclosure.

FIG. 13 illustrates an example block diagram of a computer, which can bea network node, that can be operable to execute processes and methods,in accordance with various aspects and embodiments of the subjectdisclosure.

DETAILED DESCRIPTION

The following description and the annexed drawings set forth in detailcertain illustrative aspects of the subject matter. However, theseaspects are indicative of but a few of the various ways in which theprinciples of the subject matter can be implemented or employed. Otheraspects, advantages, and novel features of the disclosed subject matterwill become apparent from the following detailed description whenconsidered in conjunction with the provided drawings. In the followingdescription, for purposes of explanation, numerous specific details areset forth to provide a understanding of the subject disclosure. It maybe evident, however, that the subject disclosure may be practicedwithout these specific details. In other instances, well-knownstructures and devices are shown in block diagram form in order tofacilitate describing the subject disclosure. For example, the methods(e.g., processes and logic flows) described in this specification can beperformed by devices (e.g., a user equipment (UE), a network nodedevice, etc.) comprising programmable processors that execute machineexecutable instructions to facilitate performance of operationsdescribed herein. Examples of such devices can be devices comprisingcircuitry and components as described in FIG. 12 and FIG. 13.

The present patent application relates to reduced (or some might use theterm simplified) physical layer communications procedures (reducedphysical layer communications procedures) that can be implemented when auser equipment (UE) enters a battery power saving mode of operation.Example reduced physical layer procedures (also referred to as physicallayer communications procedures) can be implemented based on reducedcapabilities indicated by the UE. Example embodiments of reducedphysical layer procedures can also be implemented based on the networknode's reconfiguration of parameters to facilitate the activation of thereduced physical layer communications procedures, once the network nodeis notified by the UE that it is entering a battery saving mode. Inexample embodiments, the UE can also send to the network noderecommendations of reduced physical layer procedures, which the networknode can accept in whole or part, reject, or add to.

FIG. 1 illustrates an example mobile communication system 100 (alsoreferred to as mobile system 100) in accordance with various aspects andembodiments of the subject disclosure. In example embodiments (alsoreferred to as non-limiting embodiments), mobile system 100 can comprisea mobile (also referred to as cellular) network 106, which can compriseone or more mobile networks typically operated by communication serviceproviders (e.g., mobile network 106). The mobile system 100 can alsocomprise one or more user equipment (UE) 102 _(1-n) (also referred to asuser devices). The UEs 102 _(1-n) can communicate with one another viaone or more network node devices (also referred to as network nodes) 104_(1-n) (referred to as network node 104 in the singular) of the mobilenetwork 106. The dashed arrow lines from the network nodes 104 _(1-n) tothe UE 102 _(1-n) represent downlink (DL) communications and the solidarrow lines from the UE 102 _(1-n) to the network nodes 104 _(1-n)represent uplink (UL) communications.

UE 102 can comprise, for example, any type of device that cancommunicate with mobile network 106, as well as other networks (seebelow). The UE 102 can have one or more antenna panels having verticaland horizontal elements. Examples of a UE 102 comprise a target device,device to device (D2D) UE, machine type UE, or UE capable of machine tomachine (M2M) communications, personal digital assistant (PDA), tablet,mobile terminal, smart phone, laptop mounted equipment (LME), universalserial bus (USB) dongles enabled for mobile communications, a computerhaving mobile capabilities, a mobile device such as cellular phone, adual mode mobile handset, a laptop having laptop embedded equipment(LEE, such as a mobile broadband adapter), a tablet computer having amobile broadband adapter, a wearable device, a virtual reality (VR)device, a heads-up display (HUD) device, a smart car, a machine-typecommunication (MTC) device, and the like. UE 102 can also comprise IOTdevices that communicate wirelessly.

Mobile network 106 can include various types of disparate networksimplementing various transmission protocols, including but not limitedto cellular networks, femto networks, picocell networks, microcellnetworks, internet protocol (IP) networks, Wi-Fi networks associatedwith the mobile network (e.g., a Wi-Fi “hotspot” implemented by a mobilehandset), and the like. For example, in at least one implementation,mobile network 100 can be or can include a large scale wirelesscommunication network that spans various geographic areas, and comprisevarious additional devices and components (e.g., additional networkdevices, additional UEs, network server devices, etc.).

Still referring to FIG. 1, mobile network 106 can employ variouscellular systems, technologies, and modulation schemes to facilitatewireless radio communications between devices (e.g., the UE 102 and thenetwork node 104). While example embodiments might be described for 5Gnew radio (NR) systems, the embodiments can be applicable to any radioaccess technology (RAT) or multi-RAT system where the UE operates usingmultiple carriers. For example, mobile system 100 can be of any variety,and operate in accordance with standards, protocols (also referred to asschemes), and network architectures, including but not limited to:global system for mobile communications (GSM), 3GSM, GSM Enhanced DataRates for Global Evolution (GSM EDGE) radio access network (GERAN),Universal Mobile Telecommunications Service (UMTS), General Packet RadioService (GPRS), Evolution-Data Optimized (EV-DO), Digital EnhancedCordless Telecommunications (DECT), Digital AMPS (IS-136/TDMA),Integrated Digital Enhanced Network (iDEN), Long Term Evolution (LTE),LTE Frequency Division Duplexing (LTE FUD), LTE time division duplexing(LTE TDD), Time Division LTE (TD-LTE), LTE Advanced (LTE-A), TimeDivision LTE Advanced (TD-LTE-A), Advanced eXtended Global Platform(AXGP), High Speed Packet Access (HSPA), Code Division Multiple Access(CDMA), Wideband CDMA (WCMDA), CDMA2000, Time Division Multiple Access(TDMA), Frequency Division Multiple Access (FDMA), Multi-carrier CodeDivision Multiple Access (MC-CDMA), Single-carrier Code DivisionMultiple Access (SC-CDMA), Single-carrier FDMA (SC-FDMA), OrthogonalFrequency Division Multiplexing (OFDM), Discrete Fourier TransformSpread OFDM (DFT-spread OFDM), Single Carrier FDMA (SC-FDMA), FilterBank Based Multi-carrier (FBMC), zero tail DFT-spread-OFDM (ZTDFT-s-OFDM), Unique Word OFDM (UW-OFDM), Unique Word DFT-spread OFDM (UWDFT-Spread-OFDM), Cyclic Prefix OFDM (CP-OFDM), resource-block-filteredOFDM, Generalized Frequency Division Multiplexing (GFDM), Fixed-mobileConvergence (FMC), Universal Fixed-mobile Convergence (UFMC), MultiRadio Bearers (RAB), Wi-Fi, Worldwide Interoperability for MicrowaveAccess (WiMax), and the like.

Still referring to FIG. 1, in example embodiments, UE 102 can becommunicatively coupled (or in other words, connected) to a network node104 of the mobile network 106. Network node 104 can have a cabinet andother protected enclosures, an antenna mast, and multiple antennas forperforming various transmission operations (e.g., MIMO operations). Eachnetwork node 104 can serve several cells, also called sectors, dependingon the configuration and type of antenna. Network node 104 can compriseNodeB devices, base station (BS) devices, mobile stations, access point(AP) devices, and radio access network (RAN) devices. Network node 104can also include multi-standard radio (MSR) radio node devices,including but not limited to: an MSR BS, an eNode B device (e.g.,evolved NodeB), a network controller, a radio network controller (RNC),a base station controller (BSC), a relay, a donor node controllingrelay, a base transceiver station (BTS), an access point, a transmissionpoint (TP), a transmission/receive point (TRP), a transmission node, aremote radio unit (RRU, described further below), a remote radio head(RRH), nodes in distributed antenna system (DAS), and the like. In 5Gterminology, the network node is referred to by some as a gNodeB device.

Still referring to FIG. 1, in various embodiments, mobile network 106can be configured to provide and employ 5G cellular networking featuresand functionalities. 5G wireless communication networks are expected tofulfill the demand of exponentially increasing data traffic and to allowpeople and machines to enjoy gigabit data rates with virtually zerolatency. Compared to 4G, 5G supports more diverse traffic scenarios. Forexample, in addition to the various types of data communication betweenconventional UEs (e.g., phones, smartphones, tablets, PCs, televisions,Internet enabled televisions, etc.) supported by 4G networks, 5Gnetworks can be employed to support data communication between smartcars in association with driverless car environments, as well as machinetype communications (MTCs). Considering the different communicationneeds of these different traffic scenarios, the ability to dynamicallyconfigure waveform parameters based on traffic scenarios while retainingthe benefits of multi carrier modulation schemes (e.g., OFDM and relatedschemes) can provide a significant contribution to the highspeed/capacity and low latency demands of 5G networks. With waveformsthat split the bandwidth into several sub-bands, different types ofservices can be accommodated in different sub-bands with the mostsuitable waveform and numerology, leading to an improved spectrumutilization for 5G networks.

Still referring to FIG. 1, to meet the demand for data centricapplications, features of proposed 5G networks may comprise: increasedpeak bit rate (e.g., 20 Gbps), larger data volume per unit area (e.g.,high system spectral efficiency—for example about 3.5 times that ofspectral efficiency of long term evolution (LTE) systems), high capacitythat allows more device connectivity both concurrently andinstantaneously, lower battery/power consumption (which reduces energyand consumption costs), better connectivity regardless of the geographicregion in which a user is located, a larger numbers of devices, lowerinfrastructural development costs, and higher reliability of thecommunications. Thus, 5G networks may allow for: data rates of severaltens of megabits per second should be supported for tens of thousands ofusers, 1 Gbps to be offered simultaneously to tens of workers on thesame office floor, for example; several hundreds of thousands ofsimultaneous connections to be supported for massive sensor deployments;improved coverage, enhanced signaling efficiency; reduced latencycompared to LTE.

Referring to FIG. 2, in one technique to meet increasing demand (andcontrol costs), small cell deployments are being implemented with cloudradio access network (also referred to as Cloud-RAN, C-RAN, CRAN,centralized-RAN) systems, wherein a portion of a base station device(e.g., the baseband unit (BBU) device 204 of a node 104, e.g., a gNodeB)may support multiple remote radio unit (RRU) devices 202. In theseexample embodiments, the RRU devices 202 can be primarily used fortransmission and reception of radio signals from UEs 102 (e.g., RFprocessing), while the BBU devices 204 can be used as the processingunit of telecom systems. BBU devices 204 can be of a smaller, modulardesign allowing for higher integration, lower power consumption andeasier deployment. In a typical arrangement, a BBU device 204 can beplaced in the equipment room and connected (also referred to as coupled)with the multiple RRUs 202 via communications links (e.g., opticalfiber). In some embodiments, the RRUs 202 can be physically located atsome distance from the BBUs. Thus, instead of deploying more networknodes having the full capabilities performed by the RRU and BBU, thenetwork can thus have many RRUs coupled to a BBU.

Also, to aid in increasing capacity, the upcoming 5G access network mayutilize higher frequencies (e.g., >6 GHz). Currently, much of themillimeter wave (mmWave) spectrum, the band of spectrum between 30gigahertz (Ghz) and 300 Ghz is underutilized, offering the availabilityof large swaths of un-used spectrum. The millimeter waves have shorterwavelengths that range from 10 millimeters to 1 millimeter. While thesenew spectrum bands in higher frequency do hold the promise of morespectrum, and therefore the ability to meet the increasing demands ofthe mobile industry as stated above, the use of these higher frequencybands also come with some significant challenges and hurdles. One of thekey issues is the poorer propagation that radio waves experience inthese high frequency bands, as these mmWave signals can experiencesevere path loss, penetration loss, and fading.

It is known that the propagation loss depends on the frequency with a 20log 10(F) dependency. This implies that for every 2× increase in thecarrier frequency, there is a 6 dB increase in the propagation loss.With more adverse propagation conditions, it is usually the uplink (UL)that starts to become a challenge, since the total transmit power islimited at the mobile device (e.g., UE 102). Current mobile devices havea total of 23 dBm (200 mWatts) (wherein dBM is sometimes referred to asdB_(mW) or decibel-milliwatts).

One of the key channels that needs to be preserved in the UL is the ULcontrol channel, also referred to as Physical Uplink Control Channel(PUCCH). In example embodiments of a mobile network (e.g., network 106),the PUCCH control signaling comprises uplink data transmittedindependently of traffic data. The PUCCH can carry various information,such as the hybrid automatic repeat request (HARQ) error controlacknowledgement/negative acknowledgement (ACK/NACK) message related tothe downlink (DL) transmission, channel state information (CSI) such aschannel quality indicator (CQI), pre-coding matrix indicator (PMI), rankindicator (RI), CSI resource indicator (CRI), etc., and schedulingrequests for uplink transmission. In example embodiments, the PUCCH cancomprise one resource block (RB) per transmission at one end of thesystem bandwidth, followed by an RB in the following slot at theopposite end of the channel spectrum, thus making use of frequencydiversity, with an estimated gain of 2 dB. A PUCCH control regioncomprises every two such RBs. Additionally, in PUCCH, a self-containedsubframe enables a transmission and ACK/NACK in the same subframe.Without the PUCCH, which can be impacted by propagation losses, there isno way for the system to maintain any DL or UL data bearers (bearerchannels can be assigned to UEs that are connected to the network, and aset of network parameters can define how the data carried on thatchannel is to be treated (e.g., best effort data, versus guaranteed),which is why the PUCCH is often designed to be robust.

Shown in FIG. 3 is a design of the PUCCH in LTE (e.g., the PUCCH formatfor LTE), wherein the columns correspond to OFDM symbols 302, and therows correspond to sub carrier indices 304. A somewhat similar designfor 5G NR can be expected as well, with minor changes. Referring to FIG.3, OFDM symbols 2-4 carry the demodulation reference signal and can alsocarry data. The density of the DMRS (also referred to as the pilotdensity) refers to the amount of DMRS signaling carried in OFDM symbols2-4 versus the amount of data carried in OFDM symbols 2-4. The DMRS isused for aiding the UL transmitter with performing channel estimationand noise variance estimation, both of which are conducive for the ULreceiver to demodulate the signal.

With improved UL waveform design and improved power amplifier technology(power amplifier), it is expected that in 5G access networks, the powercan be pushed to somewhere around 26-27 dBm (400-500 mWatts). However,this increase in power might not be enough to deal with the adversity ofthe propagation conditions in higher frequency bands.

Apart from higher power the mobile industry is also exploring othertechniques, including those related to new physical layer design andadvanced receiver designs to overcome the propagation hurdles in highfrequency bands.

In one technique, performance can be improved with the use of multipleantennas. The shorter wavelengths at mmWave frequencies allow for moreantennas to be packed in the same physical dimension, which allows forlarge-scale spatial multiplexing and highly directional beamforming.Multi-antenna techniques can significantly increase the data rates andreliability of a wireless communication system. Multiple input multipleoutput (MIMO), which was introduced in the third-generation partnershipproject (3GPP) and has been in use since (including with LTE), is amulti-antenna technique that can improve the spectral efficiency oftransmissions, thereby significantly boosting the overall data carryingcapacity of wireless systems. The use of multiple-input multiple-output(MIMO) techniques can improve mmWave communications, and has been widelyrecognized as a potentially important component for access networksoperating in higher frequencies. MIMO can be used for achievingdiversity gain, spatial multiplexing gain and beamforming gain. Forthese reasons, MIMO systems can be expected to continue to beimplemented in 5G systems.

Note that using multi-antennas does not always mean that MIMO is beingused. For example, a configuration can have two downlink antennas, andthese two antennas can be used in various ways. In addition to using theantennas in a 2×2 MIMO scheme, the two antennas can also be used in adiversity configuration rather than MIMO configuration. Even withmultiple antennas, a particular scheme might only use one of theantennas (e.g., LTE specification's transmission mode 1, which uses asingle transmission antenna and a single receive antenna). Or, only oneantenna can be used, with various different multiplexing, precodingmethods etc.

The MIMO technique uses a commonly known notation (M×N) to representMIMO configuration in terms number of transmit (M) and receive antennas(N) on one end of the transmission system. The common MIMOconfigurations used for various technologies are: (2×1), (1×2), (2×2),(4×2), (8×2) and (2×4), (4×4), (8×4). The configurations represented by(2×1) and (1×2) are special cases of MIMO known as transmit diversity(or spatial diversity) and receive diversity. In addition to transmitdiversity (or spatial diversity) and receive diversity, other techniquessuch as spatial multiplexing (comprising both open-loop andclosed-loop), beamforming, and codebook-based precoding can also be usedto address issues such as efficiency, interference, and range.

FIG. 4 illustrates an example of a multi-antenna transmission embodimenthaving multiple antenna ports. As mentioned above, arrangements withmore antenna ports are expected to be used for 5G systems. Antennamapping in general, can be described as a mapping from the output of thedata modulation 402 to the different antenna ports 404. The input 406 tothe antenna mapping component(s) 408 thus consists of the modulationsymbols (QPSK, 16QAM, 64QAM, 256QAM) corresponding to the one or twotransport blocks. To be more specific, there is one transport block pertransmission time interval (TTI), except for spatial multiplexing, inwhich case there may be up to two transport blocks per TTI. The outputof the antenna mapping comprises a set of symbols for each antenna port.The symbols of each antenna port are subsequently applied to the OFDMmodulator—that is, mapped to the basic OFDM time-frequency gridcorresponding to that antenna port.

Systems incorporating a very large number of antennas (degrees offreedom) at the network node (e.g., network node 104), for examplegreater than 8×8 (8 transmit and 8 receive antennas), can be referred toas “massive MIMO” systems (also known as Large-Scale Antenna Systems,Very Large MIMO, Hyper MIMO, Full-Dimension MIMO and ARGOS), which areexpected to be a differentiator between currently deployed LTE (4G)mobile networks and 5G mobile networks of the future. The large numberof antennas can be used in the downlink (DL) for precoding and in theuplink (UL) for multi-antenna equalization.

FIG. 5 shows a schematic figure of an example multi-antenna receiver(e.g., network node 104 comprising an RRU device 202 and BBU device 204)that can be used in the UL. The network node (also referred to as thereceiver, or UL receiver) in the present application) can benefit from alarge number of receiver antennas (degrees of freedom) since it can beused for a variety of functions such as interference cancellation,coherent combining, beam steering, null steering etc. One practicalimplementation of massive MIMO uses individual antenna elements as areceiver path, thereby making active antenna systems an enabler ofmassive MIMO in upcoming 5G cellular networks.

With massive MIMO systems it is possible to increase the UL coverage tomitigate the propagation challenges associated with higher frequencybands, as mentioned above. However, as the system continues to operateat a lower signal-to-noise-plus-interference ratio (SINR) regime (asexplained below, if more antennas are added, at some point, the SINRbegins to fall), one of the problems faced by the UL receiver is inchannel estimation. As shown in FIG. 5, the channel estimation stageoccurs before the multi-antenna equalization stage, and therefore isdone at the lower SINR, as the push for coverage extension continues.

FIG. 6 is a graph showing block error rate (BLER) versus SINR. Asmentioned above, at low SINR, channel estimation can become a challenge.Referring to FIG. 6, looking at the curves, it can be noticed that asthe number of antennas at the receiver increases, the SINR operatingpoint of the UL receiver can decrease. For a typical example mobilenetwork, the operating point can be defined as 1% BLER.

Theoretically as the number of antennas at the receiver doubles, again >3 dB can be expected. This is because at least a 3 dB array can beexpected to combine gains, and some additional gain can come fromdiversity gain. The diversity gain comes from the fact that the signalfading at the different antennas is somewhat un-correlated. Therefore,even with completely correlated fading between antennas, a 3 dB gain canbe expected if the number of antennas is doubled.

If the typical operating point of PUCCH (i.e. 1% BLER) in FIG. 6 isconsidered, it can be seen that the gain is less than 3 dB when thenumber of antennas is doubled. The 3 dB trend is seen going from 2antennas to 4 antennas, and from 4 antennas to 8 antennas. However,beyond 8 antennas we do not see the 3 dB gain as the SINR operatingpoint falls below −12 dB. This happens because errors introduced duringthe channel estimation stage at the receiver becomes more prominent whenthe operating SINR point falls below −12 dB. This is a fundamental issuewith the design of the current PUCCH channel, which doesn't allow it tooperate at very low SINR, even though the large number of receiverantennas is capable of doing so barring the issues of channel estimationerror.

In example embodiments in accordance with aspects of the presentapplication, a technique (e.g., which can involve a system, method,etc.) for adapting a demodulation reference signal (DMRS) configuration,to aid the network node (e.g., the UL receiver) with the channelestimation stage, is described herein.

In the context of this disclosure, DMRS configuration refers to both thepower as well as the density (as described above with reference to FIG.3) of the DMRS. Since the impairment of signals at the UL receiver(e.g., network node) is only known by the UL receiver, this methodincludes a closed loop solution, where the DMRS configuration and itsmodification is indicated by the UL receiver to the transmitter (e.g.,the UE). This system can adapt the power, the density, or a combinationof both, to aid the channel estimation stage of the network node moreoptimally. The proposed method allows for the UL DMRS configuration tobe adapted based on link condition, which allows for a robustperformance of the UL control channel even at low SINR conditions. Thisallows the 5G system to operate in higher frequency bands while matchingthe coverage of legacy systems such as 4G LTE in lower frequency bands.Note that the techniques proposed in this disclosure are applicable toboth downlink and uplink and side link data transmission schemes eventhough the example of UL is cited as a primary use case. In addition,the embodiments are applicable to single carrier and multi carrier(carrier aggregation) transmission schemes.

To introduce (or re-familiarize) the concepts of reference signal andclosed loop, a closed loop spatial multiplexing scheme applicable toMIMO and massive MIMO systems that uses codebook-based precoding(wherein open loop systems do not require knowledge of the channel atthe transmitter, while closed loop systems require channel knowledge atthe transmitter, provided via a feedback channel by the UE), is brieflydescribed. In this scheme, one or more reference signals RS (alsoreferred to as a pilot signal, or pilot) are first sent from the networknode (e.g., network node 104) to the UE (e.g., UE 102). The UE canevaluate the reference signals and compute the channel estimates and theparameters needed for channel state information (CSI) reporting. In LTE,the CSI report comprises, for example, the channel quality indicator(CQI), precoding matrix index (PMI), rank information (RI), CSI resourceindicator (CRI), etc. (these parameters may be similar for a 5G network,but may carry a different name, or designation). The CSI report is sentto the network node via a feedback channel either on a periodic basis oron demand based CSI (e.g., aperiodic CSI reporting). The network nodescheduler uses this information in choosing the parameters forscheduling of this particular UE. The network node sends the schedulingparameters to the UE on the downlink control channel called the physicaldownlink control channel (PDCCH). After that, actual data transfer takesplace from the network node to the UE (e.g., on the physical downlinkshared channel (PDSCH)).

In the technique that is the subject of the present application, thenetwork node (also referred to as the receiver, or UL receiver in thepresent application) evaluates a reference signal sent by the userequipment (also referred to as the transmitter in the presentapplication. This technique relates to the signaling of the DMRSconfiguration from the receiver (e.g., network node 104) to thetransmitter (e.g., UE 102), which sends a reference signal (e.g., DMRS)to the network node. Based on the evaluation of the reference signal, adetermination can be made to modify the DMRS configuration. Thistechnique can aid the channel estimation stage at channel at the networknode. The DMRS configuration is thus adapted, based on the linkconditions.

FIG. 7 describes an example method 700 for this technique that can beperformed. In example embodiments, the method can be broken down into 3stages, broadly speaking—initial configuration of the DMRS, detection ofcondition to modify (e.g., change, correct, adapt, etc.) the DMRSconfiguration, and signaling for modification of the DMRS configuration,such that the DMRS is adapted for current conditions experienced by theUE.

Referring to FIG. 7, with respect to initial configuration of the DMRS,at step 705, the network node (e.g., network node 104) selects aninitial set of configurations for the DMRS to be used by the UE. At step710, the network node then signals (e.g., sends, transmits,communicates, etc.) this initial set to the UE (e.g., UE 102). In thiscontext, the configuration of the DMRS includes aspects such as DMRSpower boost, DMRS density, amongst other things. This initialconfiguration can be accomplished (e.g., sent to the UE) using, forexample, radio resource control (RRC) signaling for the PUCCHconfiguration.

After receiving a reference signal (e.g., a sounding reference signal)from the UE (e.g. UE 102) at step 715, the receiver at step 720evaluates the reference signal received from the UE and determineswhether the current DMRS configuration is suitable for the linkconditions experienced by the UE. This can be done based on estimates ofSINR, error rate, path loss, location of the UE in the cell, etc. andcan be left up to the receiver implementation. In response to adetermination that the current DMRS configuration is applicable for theconditions, the receiver (e.g., the network node 104) does not send anysignals calling for the adaptation of the DMRS configuration (e.g., doesnothing related to the modification of the DMRS configuration).

In response to the receiver detecting that a condition has been met (orexample, if the SINR is below is a specific threshold, or the error rateis very high over a period of time, etc.) where the current DMRSconfiguration is not applicable (not appropriate for the conditions), ornot suitable for the conditions), then the method proceeds to step 730.At step 730, the receiver can signal to the transmitter (e.g., UE) formodification of the DMRS configuration. This signaling can be doneeither via layer 3 (L3) signaling (RRC configuration), or layer 1 (L1)signaling (downlink control information/uplink control informationDCI/UCI, wherein DCI relates to any information transmitted on thephysical downlink control channel (PDCCH), and UCI relates to anyinformation transmitted on the PUCCH. The choice of whether L3 vs L1signaling is performed might depend on which aspect of the DMRSconfiguration is being modified. For example, if modification of theDMRS density is desired, L3 signaling might be more suitable, whereassignaling a modification to power boosting/scaling can be done via L1signaling. The network node can, for example, have a table thatindicates which configuration to select based on which conditions. Inother example embodiments, the network node can modify the DMRSconfiguration, and if a modification was made, can be sent to the UE(e.g., as part of RRC signaling). The transmitter (e.g., UE) can then,based on the signaling to modify, adapt the DMRS configuration.

FIG. 8 is a transaction diagram showing an example with messagesequences related to the signaling of the DMRS configurationmodification. At transaction (1), after the network node (e.g., networknode 104) selects an initial set of configurations for the DMRS to beused by the UE, the network node signals (e.g., sends, transmits,communicates, etc.) the initial DMRS configuration to the UE (e.g., UE102). In this context, the configuration of the DMRS includes aspectssuch as DMRS power boost, DMRS density, amongst other things. Thisinitial configuration can be accomplished (e.g., sent to the UE) using,for example, radio resource control (RRC) signaling for the PUCCHconfiguration.

After receiving a reference signal (e.g., a sounding reference signal)from the UE (e.g. UE 102) sent in transaction (2), the network node(e.g., the receiver of the network node) can at stage 804 determinewhether the current DMRS configuration is suitable for the linkconditions experienced by the UE. This can be done based on estimates ofSINR, error rate, path loss, location of the UE in the cell, etc. andcan be left up to the receiver implementation. In response to adetermination that the current DMRS configuration is applicable for theconditions, the receiver does not send any signals calling for theadaptation of the DMRS configuration (e.g., does nothing related to themodification of the DMRS configuration). In response to the receiverdetects a condition has been met where the current DMRS configuration isnot applicable (for example, if the SINR is below is a specificthreshold, or the error rate is very high over a period of time, etc.),then the receiver (e.g., network node) can signal to the transmitter(e.g., the UE) of the network node for modification of the DMRSconfiguration. This signaling can be done either via layer 3 (L3)signaling (RRC configuration), or layer 1 (L1) signaling (downlinkcontrol information/uplink control information DCI/UCI). The choice ofwhether L3 vs L1 signaling is performed might depend on which aspect ofthe DMRS configuration is being modified. For example, if modificationof the DMRS density us desired, L3 signaling might be more suitable,whereas signaling a modification to power boosting/scaling can be donevia L1 signaling.

Still referring to FIG. 8, at transaction (3) a message comprising themodified DMRS configuration, if a modification was needed, can be sentto the UE. In other example embodiments, the network node can signal theUE to modify its DMRS configuration.

In accordance with some example embodiments, a computing device (e.g.,network node 104) can be operable to perform example methods andoperations, as illustrated in flow diagrams as shown in FIGS. 9-11 anddescribed in the corresponding text, in accordance with various aspectsand embodiments of the subject disclosure. Additionally,machine-readable storage medium, comprising executable instructionsthat, when executed by a processor, can also facilitate performance ofthe methods and operations described in FIGS. 9-11.

In non-limiting embodiments (also referred to as example embodiments), anetwork device (e.g., network node 104), comprising a processor and amemory that stores executable instructions that, when executed by theprocessor, facilitate performance of example operations 900, as shown inFIG. 9. The network device can comprise antennas, and be operable to usethe antennas to communicate via a massive multiple in multiple outprotocol.

The operations can comprise, at step 905, determining configuration datarepresentative of a configuration for a first demodulation referencesignal (e.g., DMRS) that is used to facilitate performing a firstestimation of a transmission channel and a second estimation of a noisevariance for transmissions between the network device (e.g., networknode 104, receiver, uplink receiver) and a user equipment (e.g., UE 102,transmitter). The configuration data can be, for example, an initial setof configurations for the DMRS.

At step 910, the operations can further comprise transmitting theconfiguration data to the user equipment.

At step 915, the operations can further comprise facilitating receivinga second reference signal from the user equipment.

The operations can further comprise, at step 920, evaluating the secondreference signal to determine whether the configuration data is suitablefor a condition of a transmission link between the network device andthe user equipment.

The operations at step 925, further comprise, in response to adetermination that the configuration is not suitable for the condition,modifying the configuration data resulting in modified configurationdata representative of a modified configuration for the firstdemodulation reference signal. The determination can be based onestimates of a signal-to-noise-plus-interference ratio indicative of apropagation loss for information transmitted on the transmission link.The determination can also be based on an error rate related to errorsin transmission experienced by the transmission link.

The operations can also comprise, in some example embodiments,transmitting the modified configuration data to the user equipment. Insome example embodiments, the transmissions can be made using a layer 3protocol related to radio resource control signaling. In some exampleembodiments, the transmissions can be made a layer 1 protocol related toinformation communicated via a physical control channel.

In some example embodiments, the network device can comprise a remoteradio unit device, wherein the remote radio unit device (e.g., RRU 202)is coupled to baseband unit device (e.g., BBU 204). The RRU can becoupled to the BBU by, for example, a fiber link. If the network devicecan be thought of as comprising both the RRU and the BBU, then thenetwork device can also be referred to as a system.

Moving to FIG. 10, in non-limiting embodiments (also referred to asexample embodiments), a network device (e.g., network node 104),comprising a processor and a memory that stores executable instructionsthat, when executed by the processor, facilitate performance of exampleoperations 1000, as shown in FIG. 10.

The operations can comprise, at step 1005, determining a configurationfor a first demodulation reference signal (e.g., DMRS) used to performchannel estimation and noise variance estimation for transmissionsbetween the network device (e.g., UE 104, receiver, UL receiver) to auser equipment (e.g., UE 102, transmitter).

The operations 1000 at step 1010 can further comprise transmitting theconfiguration to the user equipment.

The operations 1000 at step 1015 can further comprise facilitatingreceiving a second reference signal from the user equipment.

The operations 1000 can further comprise at step 1020, in response to adetermination, based on an evaluation of the second reference signalreceived from the user equipment, that the configuration is not suitablefor a condition, signaling the user equipment to modify theconfiguration.

In some example embodiments, the network device can comprise a remoteradio unit device (e.g., RRU 202). In some example embodiments, theremote radio unit device can be coupled to (e.g., connected to,communicatively connected to, communicatively coupled to, etc.) abaseband unit device (e.g., BBU 204). The RRU can be coupled to the BBUby, for example, a fiber link.

In example embodiments, the determination can be based on estimates of asignal-to-noise-plus-interference ratio (e.g., SINR). The SINR can beindicative of a propagation loss for information transmitted on thetransmission link. The determination can also be based on an error rate.The error rate can be related to errors in transmission experienced bythe transmission link. The network device can further comprise antennas,and the network device can be operable to use the antennas tocommunicate via a massive multiple in multiple out protocol (e.g.,massive MIMO).

Now referring to FIG. 11, in non-limiting embodiments, a method 1100 canbe performed by the network node device (e.g., network node 104). Themethod 1100 can begin at step 1105, wherein the method can comprisedetermining, by a network node device (e.g., network node 104, receiver,UL receiver) comprising a processor, a configuration for a firstdemodulation reference signal used for performing channel estimation andnoise variance estimation for a transmission from the network nodedevice to a user equipment (e.g., UE 102, transmitter).

The method 1100 can further comprise at step 1110, transmitting, by thenetwork node device, the configuration to the user equipment.

At step 1115, the method can further comprise facilitating receiving, bythe network node device, a second reference signal from the userequipment.

The method 1100 can further comprise, at 1120, in response to adetermination, based on an evaluation of the second reference signalreceived from the user equipment, that the configuration is notappropriate for a condition of a transmission link between the networknode and the user equipment, transmitting, by the network node device, asignal to the user equipment to modify the configuration.

In example embodiments, the configuration (e.g., DMRS configuration)relates to a density representative of an amount of a physical upstreamcontrol channel occupied by demodulation reference signal information,and can also relate to an amount of transmit power used by the userequipment. The network node device (which can also be referred to as asystem) can comprise a remote radio unit device (e.g., RRU 202), and abaseband unit device (e.g., BBU 204) connected to the remote radio unitdevice.

Referring now to FIG. 12, illustrated is a schematic block diagram of auser equipment (e.g., UE 102, etc.) that can be a mobile device 1200capable of connecting to a network in accordance with some embodimentsdescribed herein. Although a mobile handset 1200 is illustrated herein,it will be understood that other devices can be a mobile device, andthat the mobile handset 1200 is merely illustrated to provide contextfor the embodiments of the various embodiments described herein. Thefollowing discussion is intended to provide a brief, general descriptionof an example of a suitable environment 1200 in which the variousembodiments can be implemented. While the description includes a generalcontext of computer-executable instructions embodied on amachine-readable storage medium, those skilled in the art will recognizethat the innovation also can be implemented in combination with otherprogram modules and/or as a combination of hardware and software.

Generally, applications (e.g., program modules) can include routines,programs, components, data structures, etc., that perform particulartasks or implement particular abstract data types. Moreover, thoseskilled in the art will appreciate that the methods described herein canbe practiced with other system configurations, includingsingle-processor or multiprocessor systems, minicomputers, mainframecomputers, as well as personal computers, hand-held computing devices,microprocessor-based or programmable consumer electronics, and the like,each of which can be operatively coupled to one or more associateddevices.

A computing device can typically include a variety of machine-readablemedia. Machine-readable media can be any available media that can beaccessed by the computer and includes both volatile and non-volatilemedia, removable and non-removable media. By way of example and notlimitation, computer-readable media can comprise computer storage mediaand communication media. Computer storage media can include volatileand/or non-volatile media, removable and/or non-removable mediaimplemented in any method or technology for storage of information, suchas computer-readable instructions, data structures, program modules orother data. Computer storage media can include, but is not limited to,RAM, ROM, EEPROM, flash memory or other memory technology, CD ROM,digital video disk (DVD) or other optical disk storage, magneticcassettes, magnetic tape, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to store thedesired information and which can be accessed by the computer.

Communication media typically embodies computer-readable instructions,data structures, program modules or other data in a modulated datasignal such as a carrier wave or other transport mechanism, and includesany information delivery media. The term “modulated data signal” means asignal that has one or more of its characteristics set or changed insuch a manner as to encode information in the signal. By way of example,and not limitation, communication media includes wired media such as awired network or direct-wired connection, and wireless media such asacoustic, RF, infrared and other wireless media. Combinations of the anyof the above should also be included within the scope ofcomputer-readable media.

The handset 1200 includes a processor 1202 for controlling andprocessing all onboard operations and functions. A memory 1204interfaces to the processor 1202 for storage of data and one or moreapplications 1206 (e.g., a video player software, user feedbackcomponent software, etc.). Other applications can include voicerecognition of predetermined voice commands that facilitate initiationof the user feedback signals. The applications 1206 can be stored in thememory 1204 and/or in a firmware 1208, and executed by the processor1202 from either or both the memory 1204 or/and the firmware 1208. Thefirmware 1208 can also store startup code for execution in initializingthe handset 1200. A communications component 1210 interfaces to theprocessor 1202 to facilitate wired/wireless communication with externalsystems, e.g., cellular networks, VoIP networks, and so on. Here, thecommunications component 1210 can also include a suitable cellulartransceiver 1211 (e.g., a global GSM transceiver) and/or an unlicensedtransceiver 1213 (e.g., Wi-Fi, WiMax) for corresponding signalcommunications. The handset 1200 can be a device such as a cellulartelephone, a PDA with mobile communications capabilities, andmessaging-centric devices. The communications component 1210 alsofacilitates communications reception from terrestrial radio networks(e.g., broadcast), digital satellite radio networks, and Internet-basedradio services networks.

The handset 1200 includes a display 1212 for displaying text, images,video, telephony functions (e.g., a Caller ID function), setupfunctions, and for user input. For example, the display 1212 can also bereferred to as a “screen” that can accommodate the presentation ofmultimedia content (e.g., music metadata, messages, wallpaper, graphics,etc.). The display 1212 can also display videos and can facilitate thegeneration, editing and sharing of video quotes. A serial I/O interface1214 is provided in communication with the processor 1202 to facilitatewired and/or wireless serial communications (e.g., USB, and/or IEEE1394) through a hardwire connection, and other serial input devices(e.g., a keyboard, keypad, and mouse). This supports updating andtroubleshooting the handset 1200, for example. Audio capabilities areprovided with an audio I/O component 1216, which can include a speakerfor the output of audio signals related to, for example, indication thatthe user pressed the proper key or key combination to initiate the userfeedback signal. The audio I/O component 1216 also facilitates the inputof audio signals through a microphone to record data and/or telephonyvoice data, and for inputting voice signals for telephone conversations.

The handset 1200 can include a slot interface 1218 for accommodating aSIC (Subscriber Identity Component) in the form factor of a cardSubscriber Identity Module (SIM) or universal SIM 1220, and interfacingthe SIM card 1220 with the processor 1202. However, it is to beappreciated that the SIM card 1220 can be manufactured into the handset1200, and updated by downloading data and software.

The handset 1200 can process IP data traffic through the communicationcomponent 1210 to accommodate IP traffic from an IP network such as, forexample, the Internet, a corporate intranet, a home network, a personarea network, etc., through an ISP or broadband cable provider. Thus,VoIP traffic can be utilized by the handset 1200 and IP-based multimediacontent can be received in either an encoded or decoded format.

A video processing component 1222 (e.g., a camera) can be provided fordecoding encoded multimedia content. The video processing component 1222can aid in facilitating the generation, editing and sharing of videoquotes. The handset 1200 also includes a power source 1224 in the formof batteries and/or an AC power subsystem, which power source 1224 caninterface to an external power system or charging equipment (not shown)by a power 110 component 1226.

The handset 1200 can also include a video component 1230 for processingvideo content received and, for recording and transmitting videocontent. For example, the video component 1230 can facilitate thegeneration, editing and sharing of video quotes. A location trackingcomponent 1232 facilitates geographically locating the handset 1200. Asdescribed hereinabove, this can occur when the user initiates thefeedback signal automatically or manually. A user input component 1234facilitates the user initiating the quality feedback signal. The userinput component 1234 can also facilitate the generation, editing andsharing of video quotes. The user input component 1234 can include suchconventional input device technologies such as a keypad, keyboard,mouse, stylus pen, and/or touch screen, for example.

Referring again to the applications 1206, a hysteresis component 1236facilitates the analysis and processing of hysteresis data, which isutilized to determine when to associate with the access point. Asoftware trigger component 1238 can be provided that facilitatestriggering of the hysteresis component 1238 when the Wi-Fi transceiver1213 detects the beacon of the access point. A session enable protocol(SIP) client 1240 enables the handset 1200 to support SIP protocols andregister the subscriber with the SIP registrar server. The applications1206 can also include a client 1242 that provides at least thecapability of discovery, play and store of multimedia content, forexample, music.

The handset 1200, as indicated above related to the communicationscomponent 1210, includes an indoor network radio transceiver 1213 (e.g.,Wi-Fi transceiver). This function supports the indoor radio link, suchas IEEE 802.11, for the handset 1200. The handset 1200 can accommodateat least satellite radio services through a handset that can combinewireless voice and digital radio chipsets into a single handheld device.

Referring now to FIG. 17, there is illustrated a block diagram of acomputer 1700 operable to execute the functions and operations performedin the described example embodiments. For example, a network node (e.g.,network node 104) may contain components as described in FIG. 17. Thecomputer 1700 can provide networking and communication capabilitiesbetween a wired or wireless communication network and a server and/orcommunication device. In order to provide additional context for variousaspects thereof, FIG. 17 and the following discussion are intended toprovide a brief, general description of a suitable computing environmentin which the various aspects of the innovation can be implemented tofacilitate the establishment of a transaction between an entity and athird party. While the description above is in the general context ofcomputer-executable instructions that can run on one or more computers,those skilled in the art will recognize that the innovation also can beimplemented in combination with other program modules and/or as acombination of hardware and software.

Generally, program modules include routines, programs, components, datastructures, etc., that perform particular tasks or implement particularabstract data types. Moreover, those skilled in the art will appreciatethat the inventive methods can be practiced with other computer systemconfigurations, including single-processor or multiprocessor computersystems, minicomputers, mainframe computers, as well as personalcomputers, hand-held computing devices, microprocessor-based orprogrammable consumer electronics, and the like, each of which can beoperatively coupled to one or more associated devices.

The illustrated aspects of the innovation can also be practiced indistributed computing environments where certain tasks are performed byremote processing devices that are linked through a communicationsnetwork. In a distributed computing environment, program modules can belocated in both local and remote memory storage devices.

Computing devices typically include a variety of media, which caninclude computer-readable storage media or communications media, whichtwo terms are used herein differently from one another as follows.

Computer-readable storage media can be any available storage media thatcan be accessed by the computer and includes both volatile andnonvolatile media, removable and non-removable media. By way of example,and not limitation, computer-readable storage media can be implementedin connection with any method or technology for storage of informationsuch as computer-readable instructions, program modules, structureddata, or unstructured data. Computer-readable storage media can include,but are not limited to, RAM, ROM, EEPROM, flash memory or other memorytechnology, CD-ROM, digital versatile disk (DVD) or other optical diskstorage, magnetic cassettes, magnetic tape, magnetic disk storage orother magnetic storage devices, or other tangible and/or non-transitorymedia which can be used to store desired information. Computer-readablestorage media can be accessed by one or more local or remote computingdevices, e.g., via access requests, queries or other data retrievalprotocols, for a variety of operations with respect to the informationstored by the medium.

Communications media can embody computer-readable instructions, datastructures, program modules or other structured or unstructured data ina data signal such as a modulated data signal, e.g., a carrier wave orother transport mechanism, and includes any information delivery ortransport media. The term “modulated data signal” or signals refers to asignal that has one or more of its characteristics set or changed insuch a manner as to encode information in one or more signals. By way ofexample, and not limitation, communication media include wired media,such as a wired network or direct-wired connection, and wireless mediasuch as acoustic, RF, infrared and other wireless media.

With reference to FIG. 13, implementing various aspects described hereinwith regards to devices (e.g., network node 104) can include a computer1300, the computer 1300 including a processing unit 1304, a systemmemory 1306 and a system bus 1308. The system bus 1308 couples systemcomponents including, but not limited to, the system memory 1306 to theprocessing unit 1304. The processing unit 1304 can be any of variouscommercially available processors. Dual microprocessors and othermulti-processor architectures can also be employed as the processingunit 1304.

The system bus 1308 can be any of several types of bus structure thatcan further interconnect to a memory bus (with or without a memorycontroller), a peripheral bus, and a local bus using any of a variety ofcommercially available bus architectures. The system memory 1306includes read-only memory (ROM) 1327 and random access memory (RAM)1312. A basic input/output system (BIOS) is stored in a non-volatilememory 1327 such as ROM, EPROM, EEPROM, which BIOS contains the basicroutines that help to transfer information between elements within thecomputer 1300, such as during start-up. The RAM 1312 can also include ahigh-speed RAM such as static RAM for caching data.

The computer 1300 further includes an internal hard disk drive (HDD)1314 (e.g., EIDE, SATA), which internal hard disk drive 1314 can also beconfigured for external use in a suitable chassis (not shown), amagnetic floppy disk drive (FDD) 1316, (e.g., to read from or write to aremovable diskette 1318) and an optical disk drive 1320, (e.g., readinga CD-ROM disk 1322 or, to read from or write to other high capacityoptical media such as the DVD). The hard disk drive 1314, magnetic diskdrive 1316 and optical disk drive 1320 can be connected to the systembus 1308 by a hard disk drive interface 1324, a magnetic disk driveinterface 1326 and an optical drive interface 1328, respectively. Theinterface 1324 for external drive implementations includes at least oneor both of Universal Serial Bus (USB) and IEEE 1294 interfacetechnologies. Other external drive connection technologies are withincontemplation of the subject innovation.

The drives and their associated computer-readable media providenonvolatile storage of data, data structures, computer-executableinstructions, and so forth. For the computer 1300 the drives and mediaaccommodate the storage of any data in a suitable digital format.Although the description of computer-readable media above refers to aHDD, a removable magnetic diskette, and a removable optical media suchas a CD or DVD, it should be appreciated by those skilled in the artthat other types of media which are readable by a computer 1300, such aszip drives, magnetic cassettes, flash memory cards, cartridges, and thelike, can also be used in the example operating environment, andfurther, that any such media can contain computer-executableinstructions for performing the methods of the disclosed innovation.

A number of program modules can be stored in the drives and RAM 1312,including an operating system 1330, one or more application programs1332, other program modules 1334 and program data 1336. All or portionsof the operating system, applications, modules, and/or data can also becached in the RAM 1312. It is to be appreciated that the innovation canbe implemented with various commercially available operating systems orcombinations of operating systems.

A user can enter commands and information into the computer 1300 throughone or more wired/wireless input devices, e.g., a keyboard 1338 and apointing device, such as a mouse 1340. Other input devices (not shown)may include a microphone, an IR remote control, a joystick, a game pad,a stylus pen, touch screen, or the like. These and other input devicesare often connected to the processing unit 1304 through an input deviceinterface 1342 that is coupled to the system bus 1308, but can beconnected by other interfaces, such as a parallel port, an IEEE 2394serial port, a game port, a USB port, an IR interface, etc.

A monitor 1344 or other type of display device is also connected to thesystem bus 1308 through an interface, such as a video adapter 1346. Inaddition to the monitor 1344, a computer 1300 typically includes otherperipheral output devices (not shown), such as speakers, printers, etc.

The computer 1300 can operate in a networked environment using logicalconnections by wired and/or wireless communications to one or moreremote computers, such as a remote computer(s) 1348. The remotecomputer(s) 1348 can be a workstation, a server computer, a router, apersonal computer, portable computer, microprocessor-based entertainmentdevice, a peer device or other common network node, and typicallyincludes many or all of the elements described relative to the computer,although, for purposes of brevity, only a memory/storage device 1350 isillustrated. The logical connections depicted include wired/wirelessconnectivity to a local area network (LAN) 1352 and/or larger networks,e.g., a wide area network (WAN) 1354. Such LAN and WAN networkingenvironments are commonplace in offices and companies, and facilitateenterprise-wide computer networks, such as intranets, all of which mayconnect to a global communications network, e.g., the Internet.

When used in a LAN networking environment, the computer 1300 isconnected to the local network 1352 through a wired and/or wirelesscommunication network interface or adapter 1356. The adapter 1356 mayfacilitate wired or wireless communication to the LAN 1352, which mayalso include a wireless access point disposed thereon for communicatingwith the wireless adapter 1356.

When used in a WAN networking environment, the computer 1300 can includea modem 1358, or is connected to a communications server on the WAN1354, or has other means for establishing communications over the WAN1354, such as by way of the Internet. The modem 1358, which can beinternal or external and a wired or wireless device, is connected to thesystem bus 1308 through the input device interface 1342. In a networkedenvironment, program modules depicted relative to the computer, orportions thereof, can be stored in the remote memory/storage device1350. It will be appreciated that the network connections shown areexemplary and other means of establishing a communications link betweenthe computers can be used.

The computer is operable to communicate with any wireless devices orentities operatively disposed in wireless communication, e.g., aprinter, scanner, desktop and/or portable computer, portable dataassistant, communications satellite, any piece of equipment or locationassociated with a wirelessly detectable tag (e.g., a kiosk, news stand,restroom), and telephone. This includes at least Wi-Fi and Bluetooth™wireless technologies. Thus, the communication can be a predefinedstructure as with a conventional network or simply an ad hoccommunication between at least two devices.

Wi-Fi, or Wireless Fidelity, allows connection to the Internet from acouch at home, a bed in a hotel room, or a conference room at work,without wires. Wi-Fi is a wireless technology similar to that used in acell phone that enables such devices, e.g., computers, to send andreceive data indoors and out; anywhere within the range of a basestation. Wi-Fi networks use radio technologies called IEEE802.11 (a, b,g, n, etc.) to provide secure, reliable, fast wireless connectivity. AWi-Fi network can be used to connect computers to each other, to theInternet, and to wired networks (which use IEEE802.3 or Ethernet). Wi-Finetworks operate in the unlicensed 2.4 and 5 GHz radio bands, at an 11Mbps (802.11b) or 54 Mbps (802.11a) data rate, for example, or withproducts that contain both bands (dual band), so the networks canprovide real-world performance similar to the basic “10BaseT” wiredEthernet networks used in many offices.

As used in this application, the terms “system,” “component,”“interface,” and the like are generally intended to refer to acomputer-related entity or an entity related to an operational machinewith one or more specific functionalities. The entities disclosed hereincan be either hardware, a combination of hardware and software,software, or software in execution. For example, a component may be, butis not limited to being, a process running on a processor, a processor,an object, an executable, a thread of execution, a program, and/or acomputer. By way of illustration, both an application running on aserver and the server can be a component. One or more components mayreside within a process and/or thread of execution and a component maybe localized on one computer and/or distributed between two or morecomputers. These components also can execute from various computerreadable storage media having various data structures stored thereon.The components may communicate via local and/or remote processes such asin accordance with a signal having one or more data packets (e.g., datafrom one component interacting with another component in a local system,distributed system, and/or across a network such as the Internet withother systems via the signal). As another example, a component can be anapparatus with specific functionality provided by mechanical partsoperated by electric or electronic circuitry that is operated bysoftware or firmware application(s) executed by a processor, wherein theprocessor can be internal or external to the apparatus and executes atleast a part of the software or firmware application. As yet anotherexample, a component can be an apparatus that provides specificfunctionality through electronic components without mechanical parts,the electronic components can comprise a processor therein to executesoftware or firmware that confers at least in part the functionality ofthe electronic components. An interface can comprise input/output (I/O)components as well as associated processor, application, and/or APIcomponents.

Furthermore, the disclosed subject matter may be implemented as amethod, apparatus, or article of manufacture using standard programmingand/or engineering techniques to produce software, firmware, hardware,or any combination thereof to control a computer to implement thedisclosed subject matter. The term “article of manufacture” as usedherein is intended to encompass a computer program accessible from anycomputer-readable device, computer-readable carrier, orcomputer-readable media. For example, computer-readable media caninclude, but are not limited to, a magnetic storage device, e.g., harddisk; floppy disk; magnetic strip(s); an optical disk (e.g., compactdisk (CD), a digital video disc (DVD), a Blu-ray Disc™ (BD)); a smartcard; a flash memory device (e.g., card, stick, key drive); and/or avirtual device that emulates a storage device and/or any of the abovecomputer-readable media.

As it employed in the subject specification, the term “processor” canrefer to substantially any computing processing unit or devicecomprising, but not limited to comprising, single-core processors;single-processors with software multithread execution capability;multi-core processors; multi-core processors with software multithreadexecution capability; multi-core processors with hardware multithreadtechnology; parallel platforms; and parallel platforms with distributedshared memory. Additionally, a processor can refer to an integratedcircuit, an application specific integrated circuit (ASIC), a digitalsignal processor (DSP), a field programmable gate array (FPGA), aprogrammable logic controller (PLC), a complex programmable logic device(CPLD), a discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. Processors can exploit nano-scale architectures suchas, but not limited to, molecular and quantum-dot based transistors,switches and gates, in order to optimize space usage or enhanceperformance of user equipment. A processor also can be implemented as acombination of computing processing units.

In the subject specification, terms such as “store,” “data store,” “datastorage,” “database,” “repository,” “queue”, and substantially any otherinformation storage component relevant to operation and functionality ofa component, refer to “memory components,” or entities embodied in a“memory” or components comprising the memory. It will be appreciatedthat the memory components described herein can be either volatilememory or nonvolatile memory, or can comprise both volatile andnonvolatile memory. In addition, memory components or memory elementscan be removable or stationary. Moreover, memory can be internal orexternal to a device or component, or removable or stationary. Memorycan comprise various types of media that are readable by a computer,such as hard-disc drives, zip drives, magnetic cassettes, flash memorycards or other types of memory cards, cartridges, or the like.

By way of illustration, and not limitation, nonvolatile memory cancomprise read only memory (ROM), programmable ROM (PROM), electricallyprogrammable ROM (EPROM), electrically erasable ROM (EEPROM), or flashmemory. Volatile memory can comprise random access memory (RAM), whichacts as external cache memory. By way of illustration and notlimitation, RAM is available in many forms such as synchronous RAM(SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rateSDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), anddirect Rambus RAM (DRRAM). Additionally, the disclosed memory componentsof systems or methods herein are intended to comprise, without beinglimited to comprising, these and any other suitable types of memory.

In particular and in regard to the various functions performed by theabove described components, devices, circuits, systems and the like, theterms (including a reference to a “means”) used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., a functional equivalent), even though not structurallyequivalent to the disclosed structure, which performs the function inthe herein illustrated example aspects of the embodiments. In thisregard, it will also be recognized that the embodiments comprise asystem as well as a computer-readable medium having computer-executableinstructions for performing the acts and/or events of the variousmethods.

Computing devices typically comprise a variety of media, which cancomprise computer-readable storage media and/or communications media,which two terms are used herein differently from one another as follows.Computer-readable storage media can be any available storage media thatcan be accessed by the computer and comprises both volatile andnonvolatile media, removable and non-removable media. By way of example,and not limitation, computer-readable storage media can be implementedin connection with any method or technology for storage of informationsuch as computer-readable instructions, program modules, structureddata, or unstructured data. Computer-readable storage media cancomprise, but are not limited to, RAM, ROM, EEPROM, flash memory orother memory technology, CD-ROM, digital versatile disk (DVD) or otheroptical disk storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices, or other tangible and/ornon-transitory media which can be used to store desired information.Computer-readable storage media can be accessed by one or more local orremote computing devices, e.g., via access requests, queries or otherdata retrieval protocols, for a variety of operations with respect tothe information stored by the medium.

On the other hand, communications media typically embodycomputer-readable instructions, data structures, program modules orother structured or unstructured data in a data signal such as amodulated data signal, e.g., a carrier wave or other transportmechanism, and comprises any information delivery or transport media.The term “modulated data signal” or signals refers to a signal that hasone or more of its characteristics set or changed in such a manner as toencode information in one or more signals. By way of example, and notlimitation, communications media comprise wired media, such as a wirednetwork or direct-wired connection, and wireless media such as acoustic,RF, infrared and other wireless media.

Further, terms like “user equipment,” “user device,” “mobile device,”“mobile,” station,” “access terminal,” “terminal,” “handset,” andsimilar terminology, generally refer to a wireless device utilized by asubscriber or user of a wireless communication network or service toreceive or convey data, control, voice, video, sound, gaming, orsubstantially any data-stream or signaling-stream. The foregoing termsare utilized interchangeably in the subject specification and relateddrawings. Likewise, the terms “access point,” “node B,” “base station,”“evolved Node B,” “cell,” “cell site,” and the like, can be utilizedinterchangeably in the subject application, and refer to a wirelessnetwork component or appliance that serves and receives data, control,voice, video, sound, gaming, or substantially any data-stream orsignaling-stream from a set of subscriber stations. Data and signalingstreams can be packetized or frame-based flows. It is noted that in thesubject specification and drawings, context or explicit distinctionprovides differentiation with respect to access points or base stationsthat serve and receive data from a mobile device in an outdoorenvironment, and access points or base stations that operate in aconfined, primarily indoor environment overlaid in an outdoor coveragearea. Data and signaling streams can be packetized or frame-based flows.

Furthermore, the terms “user,” “subscriber,” “customer,” “consumer,” andthe like are employed interchangeably throughout the subjectspecification, unless context warrants particular distinction(s) amongthe terms. It should be appreciated that such terms can refer to humanentities, associated devices, or automated components supported throughartificial intelligence (e.g., a capacity to make inference based oncomplex mathematical formalisms) which can provide simulated vision,sound recognition and so forth. In addition, the terms “wirelessnetwork” and “network” are used interchangeable in the subjectapplication, when context wherein the term is utilized warrantsdistinction for clarity purposes such distinction is made explicit.

Moreover, the word “exemplary” is used herein to mean serving as anexample, instance, or illustration. Any aspect or design describedherein as “exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or designs. Rather, use of the wordexemplary is intended to present concepts in a concrete fashion. As usedin this application, the term “or” is intended to mean an inclusive “or”rather than an exclusive “or”. That is, unless specified otherwise, orclear from context, “X employs A or B” is intended to mean any of thenatural inclusive permutations. That is, if X employs A; X employs B; orX employs both A and B, then “X employs A or B” is satisfied under anyof the foregoing instances. In addition, the articles “a” and “an” asused in this application and the appended claims should generally beconstrued to mean “one or more” unless specified otherwise or clear fromcontext to be directed to a singular form.

In addition, while a particular feature may have been disclosed withrespect to only one of several implementations, such feature may becombined with one or more other features of the other implementations asmay be desired and advantageous for any given or particular application.Furthermore, to the extent that the terms “includes” and “including” andvariants thereof are used in either the detailed description or theclaims, these terms are intended to be inclusive in a manner similar tothe term “comprising.”

The above descriptions of various embodiments of the subject disclosureand corresponding figures and what is described in the Abstract, aredescribed herein for illustrative purposes, and are not intended to beexhaustive or to limit the disclosed embodiments to the precise formsdisclosed. It is to be understood that one of ordinary skill in the artmay recognize that other embodiments having modifications, permutations,combinations, and additions can be implemented for performing the same,similar, alternative, or substitute functions of the disclosed subjectmatter, and are therefore considered within the scope of thisdisclosure. Therefore, the disclosed subject matter should not belimited to any single embodiment described herein, but rather should beconstrued in breadth and scope in accordance with the claims below.

What is claimed is:
 1. A network device, comprising: a processor; and amemory that stores executable instructions that, when executed by theprocessor, facilitate performance of operations, comprising: determiningconfiguration data representative of a configuration for a firstdemodulation reference signal that is used to facilitate performing afirst estimation of a transmission channel and a second estimation of anoise variance for transmissions between the network device and a userequipment; transmitting the configuration data to the user equipment;facilitating receiving a second reference signal from the userequipment; evaluating the second reference signal to determine whetherthe configuration data is suitable for a condition of a transmissionlink between the network device and the user equipment; and in responseto a determination that the configuration is not suitable for thecondition, modifying the configuration data resulting in modifiedconfiguration data representative of a modified configuration for thefirst demodulation reference signal.
 2. The network device of claim 1,wherein the operations further comprise transmitting the modifiedconfiguration data to the user equipment.
 3. The network device of claim2, wherein the transmitting the modified configuration comprises using alayer 3 protocol related to radio resource control signaling.
 4. Thenetwork device of claim 2, wherein the transmitting the modifiedconfiguration comprises using a layer 1 protocol related to informationcommunicated via a physical control channel.
 5. The network device ofclaim 1, wherein the network device comprises a remote radio unitdevice.
 6. The network device of claim 3, wherein the remote radio unitdevice is coupled to baseband unit device.
 7. The network device ofclaim 1, further comprising antennas, and wherein the network device isoperable to use the antennas to communicate via a massive multiple inmultiple out protocol.
 8. The network device of claim 1, wherein thedetermination is based on estimates of asignal-to-noise-plus-interference ratio indicative of a propagation lossfor information transmitted on the transmission link.
 9. The networkdevice of claim 1, wherein the determination is based on an error raterelated to errors in transmission experienced by the transmission link.10. A network device, comprising: a processor; and a memory that storesexecutable instructions that, when executed by the processor, facilitateperformance of operations, comprising: determining a configuration for afirst demodulation reference signal used to perform channel estimationand noise variance estimation for transmissions between the networkdevice to a user equipment; transmitting the configuration to the userequipment; facilitating receiving a second reference signal from theuser equipment; and in response to a determination, based on anevaluation of the second reference signal received from the userequipment, that the configuration is not suitable for a condition,signaling the user equipment to modify the configuration.
 11. Thenetwork device of claim 10, wherein the network device comprises aremote radio unit device.
 12. The network device of claim 11, whereinthe remote radio unit device is coupled to a baseband unit device. 13.The network device of claim 10, wherein the determination is based onestimates of a signal-to-noise-plus-interference ratio indicative of apropagation loss for information transmitted on a transmission linkbetween the network node and user equipment.
 14. The network device ofclaim 10, wherein the determination is based on an error rate related toerrors in transmission experienced on a transmission link between thenetwork node and the user equipment.
 15. The network device of claim 10,further comprising antennas, and wherein the network device is operableto use the antennas to communicate via a massive multiple in multipleout protocol.
 16. A method, comprising: determining, by a network nodedevice comprising a processor, a configuration for a first demodulationreference signal used for performing channel estimation and noisevariance estimation for a transmission between the network node deviceto a user equipment; transmitting, by the network node device, theconfiguration to the user equipment; facilitating receiving, by thenetwork node device, a second reference signal from the user equipment;and in response to a determination, based on an evaluation of the secondreference signal received from the user equipment, that theconfiguration is not appropriate for a condition of a transmission linkbetween the network node and the user equipment, transmitting, by thenetwork node device, a signal to the user equipment to modify theconfiguration.
 17. The method of claim 16, wherein the network nodedevice comprises a remote radio unit device.
 18. The method of claim 16,wherein the remote radio unit device is coupled to a baseband unitdevice.
 19. The method of claim 16, wherein the configuration relates toa density representative of an amount of a physical upstream controlchannel occupied by demodulation reference signal information.
 20. Themethod of claim 16, wherein the configuration relates to an amount oftransmit power used by the user equipment.